What is alarm monitoring?
How a fault in the field reaches the control room — raised, shown, acknowledged and cleared — so a problem is seen and acted on before it is found on the ground.
Alarm monitoring is how the control room finds out that something is wrong. An alarm raised at a CCR or circuit travels through the field unit and network to the ALCMS, which shows it in an alarm list, flashes and sounds it, records it in the event log and waits for the operator to acknowledge it. It is cleared only when the cause has been corrected.
Alarms carry a priority. A critical alarm, such as an open circuit that has shut the output down, needs immediate action. A warning, such as high load or rising earth leakage, lets the lights keep running but should be planned for. Monitoring also has a blind spot: if a link or field unit fails, the screen can freeze on old values, so a quiet screen is not proof of a healthy airfield. The CCR alarm system detects and reports; alarm monitoring is the receiving side.
- Raise. The CCR or circuit condition crosses a limit and an alarm is generated.
- Annunciate. The ALCMS shows, flashes and sounds it, with a priority and a time stamp.
- Acknowledge. The operator accepts it. The alarm is silenced but still active.
- Act. Tell ATC if lighting is affected, isolate and lock out, find and fix the cause.
- Clear and log. The alarm clears when the condition is gone, and the history is kept.
Alarm Monitoring Explorer
Raise an alarm
Operator action
Alarm list ALCMS SCREEN
Event log TIME-STAMPED
Teaching simulation. Circuit name, wording, times and acknowledgement rules are illustrative and vary by ALCMS and project specification.
Frequently Asked Questions
Q1What is alarm monitoring?
Watching for abnormal conditions on the lighting system from the control room. Alarms raised at the CCRs and circuits are carried over the network to the ALCMS, shown in an alarm list, acknowledged by the operator and recorded in an event log.
Q2How is alarm monitoring different from the CCR alarm system?
The CCR alarm system is the detection and reporting inside the regulator. Alarm monitoring is the receiving side: how the control room sees, prioritises, acknowledges and logs those alarms from every CCR and circuit on the airfield.
Q3What does acknowledging an alarm do?
It tells the system the operator has seen it, which normally stops the flashing and the audible signal. It does not fix anything. The alarm stays active until the cause is corrected and the condition clears.
Q4What are alarm priorities for?
So the most urgent problems are seen first. A critical alarm, such as an open circuit that has shut the output down, needs immediate action. A warning, such as high load or rising earth leakage, can be planned for but should not be ignored.
Q5Why can a quiet alarm screen be misleading?
If a link or field unit fails, the screen can freeze on the last known values and look healthy. A communications-lost alarm is itself an alarm, and status must then be checked at the CCR or in the field rather than read from the screen.
Q6Why keep an event log?
It records when each alarm was raised, acknowledged and cleared, and by whom. Repeated alarms on one circuit reveal a developing fault that a single clear-and-forget would hide, and the log supports investigation and maintenance records.
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